Control of emissions from power plant stations continue to be an important factor in the strategic planning of utility and industrial customers and in the development and application of new or advanced power generation technologies. The approach of repowering to meet new capacity demand and the need to retrofit existing systems to meet compliance, with the possibility of new and tougher environmental legislation (acid rain) and with the high cost of current pollution control equipment provide incentive to develop advanced emission control systems. In this area, advanced dry scrubbing techniques are being developed that use injection of fine sorbents into the furnace region that selectively getter gas phase contaminants such as oxides or sulfur; alkalis and other acid gas constituents. These sorbents are then collected downstream of the furnace region for disposal using conventional baghouse or electrostatic precipitator. In many instances, the quantity of sorbent material required is large and thus significantly increases the total dust and ash loading to downstream equipment. In conventional power plants such as coal boilers or waste to energy plants, this results in increased deposits, soot blowing, more rapid tube erosion, higher operating costs and lower system performance.
Advanced coal conversion systems such as pressurized, fluidized bed combustion (PFBC), coal gasification combined cycle, and the direct coal fueled gas turbine cycles that are being proposed will also benefit by minimizing carryover of ash and sorbent materials to provide emissions control and the protection of turbines from corrosion, erosion damage.
The need therefore is the development of a particulate barrier filter device capable of operating at temperatures from 500.degree. to about 2500.degree. F. that can collect potentially sticky ash and sorbent particles; be operated at reasonable pressure drop, be cleaned on-line using simple pulse jet or reverse flow principles and capable of achieving very high collection efficiencies (99.9%). Such devices must be compact (fit into relatively defined space requirements), low cost, and adaptable to various applications (i.e., large stationary power plants, small cogeneration and transportation power generation systems).